.COB File Extension

Source code file written in COBOL, an older programming language used for developing business, finance, and administrative applications; still used by many enterprise business applications.

COBOL has several variants, including COBOL-68 (the original standard) and COBOL 2002, a more recent version of the language. Therefore, make sure you have the appropriate compiler and text editor for the version of COBOL you're using for development.